Our laboratory is investigating the regulation of gene expression in early development. We have recently isolated six cDNA clones which represent developmentally regulated mRNAs enriched in the ectoderm of sea urchin embryos. These mRNAs accumulate in embyrogenesis at, or just prior to gastrulation, a critical period in sea urchin development. Some or all of these mRNAs may represent small gene families. We intend to further our understanding of these genes. We will determine more precisely the kinetics of accumulation of all six mRNAs and if the accumulation is segregated to specific regions of the embryo. As an initial step to the function of these genes, we will attempt to isolate and translate the mRNAs to determine the characteristics of the encoded proteins. We also propose to isolate the genomic sequences from a lambda recombinant library and characterize the gene families to which the mRNAs belong. We will determine if other genes with similar developmental properties are in the nearby vicinity. The ultimate goal of this investigation is a molecular understanding of how the sea urchin egg, a self-contained entity, can program the various events in early development that lead ultimately to the highly differentiated pluteus larva.